In the field of machine tools such as milling and grinding machines, it is essential that an object on which work is to be performed be firmly supported in some particular position so that machining, polishing, etc. can be done with great precision.
Different types of arrangements are used to hold such objects and it is important that a vise for holding the object, for example, be itself firmly supported on a machining table. One vise arrangement that has been used, for example, is described in U.S. Pat. No. 5,056,766 assigned to the same assignee as the present application. Such patent shows that a vise for holding a workpiece can be supported in a machine table having an inverted T-shaped slot. A support member for the vise could be slideably arranged in the inverted T-shaped slot and have cooperating surfaces to be positioned anywhere along the length of the slot. In this way, a vise could be fastened to the support member and tightened in position.
One such prior art arrangement is shown in FIG. 1. Referring to FIG. 1, the inverted T-support member 10 can be seen slideably arranged within a channel of a machining surface 11 of machine tool. The support member 10 has a lower elongated body portion 12 which is slideably engaged with the lower portion of the inverted T-shaped channel and an upper neck portion 13 which is slideably engaged with the narrower portion of the channel. Threaded holes 14 are provided in the upper surface portion of the support member 10. These threaded holes are adapted to have objects fastened thereto by screws or other fastening members threaded into the threaded holes 14. One such arrangement is shown in FIG. 3 where an object 20 is fastened to the support member 10 by an allen head machine bolt 21.
A cross-section of FIG. 1 is shown in FIG. 2 so that the construction of the prior art support member arrangement can be seen more clearly.
While the inverted T-shaped support member arrangement works adequately for most purposes, there are some disadvantages to this arrangement.
In FIG. 4 a force diagram is shown for the prior art apparatus indicated in FIGS. 1-3. It can be seen that if a force F.sub.y is applied pulling the neck portion of the support member vertically upwardly, equal and opposite forces F.sub.y /2 will be developed on the upper surfaces of the portion 12 of the support member 10.
Another inverted T-slot arrangement is shown in U.S. Pat. No. 5,060,920 assigned to the same assignee as the present invention. In addition to the T-slot arrangement such as that shown in FIG. 1 of the present application, this patent shows a dovetail arrangement formed as part of a gripping jaw for a workpiece holder in FIGS. 4 and 5 thereof.
Referring to FIG. 5 of the present application a cross-sectional view of dovetail member 71 is shown arranged in a channel 72 of a holding member 73. While the dovetail member 71 has two angled or inclined arms 74 and 76, it can be seen that the holding member 73 has one planar surface 77 and one angled or inclined surface 78.
The dovetail member 71 is mounted in the channel 72 by a cone tipped bolt 79 which is pressed against the angled surface of arm 74 to urge the angled surfaces 76 of member 71 against the angled surface 78 of the holding member 73. This arrangement is satisfactory for the intended purpose of having a quick release jaw mechanism.